Tennis ball throwing machine

ABSTRACT

A tennis ball throwing machine includes a support frame for carrying the machine, a pair of round pitching wheels, and a hopper mounted on the frame and above the pitching wheels. A ball chute connects the bottom of the hopper and a launch point that is proximate the point where the pitching wheels are closest together. The ball chute includes a plurality of guide rails that are spaced apart and open between them such that the guide rails are separated but are close enough together that they may support and carry a ball down the chute. The open rails allow for dirt and other debris to fall through the machine and away from the ball chute.

The present invention is directed to an improved tennis ball throwing machine. The improvements in the machine include a plurality of guide rails used in the ball chute that connects a ball hopper and the launch point of a ball throwing machine between two spinning wheels.

BACKGROUND

Tennis ball throwing machines have been manufactured and used widely for many years. They are effective tools to let individuals of all skill levels practice their tennis shots. As a result of this broad usage, there are some challenging issues that have been recognized with respect to these throwing machines, but have not yet been solved.

One important issue with tennis ball throwing machines is dirt and debris. Specifically, excessive tennis ball fuzz, pollen, clay, dust, and other dirt may collect on tennis balls. This dirt and sticks, twigs, and leaves can easily and often does come off a ball and builds up inside a tennis ball throwing machine and especially in the chute that feeds balls to the pitching wheels. If there is excessive dirt and debris build up, then it may affect the consistency and, if bad enough, the actual operation of the throwing machine. This dirt build up may, especially for heavily used machines, require frequent service for cleaning of the machine.

Another issue with tennis ball throwing machines generally is the consistent, regular feed of tennis balls from a tennis ball hopper to the pitching wheels. If there is a ball jam issue in the hopper, then time is wasted, practice is interrupted, and the user can be frustrated with the machine. Ball jams present a safety risk as well, since inexperienced users may try to resolve a jam while standing in front of and/or reaching inside of the machine.

SUMMARY

Accordingly, it is an object of the present invention to overcome the foregoing short comings with existing tennis ball throwing machines.

In one example, a tennis ball throwing machine throws balls of a selected substantially uniform compressible type. The machine comprises a support frame for carrying a pair of pitching wheels and drive motors. The pair of pitching wheels are round with their axes of rotation being substantially parallel, rotatable mounted on the support frame wherein the wheels each comprise a ball engaging peripheral surface. The respective peripheral surfaces are adjacent on another and laterally spaced such that a ball is slightly compressed when passing between the surfaces. The pair of drive motors is mounted on the support frame and connected one each to the pitching wheels to cause those wheels to rotate in opposite directions at variable speeds. A hopper is mounted on the support frame and above the pitching wheels. A ball chute is positioned in a path from the bottom of the hopper and a launch point that is proximate the point where the peripheral surfaces of the pitching wheels are closest together. The ball chute comprises a plurality of guide rails that are spaced apart and open between with the guide rails being separated at a distance apart to support and direct a ball that is carried by the rails. As a result, debris is free to fall out of and away from the ball chute.

The hopper may comprise a generally solid base but for a generally ball-sized aperture therein. The ball chute is connected proximate to the hopper at and around the aperture. The hopper may further comprise a rotating turntable mounted on the base of the hopper with the turntable have a ball-sized opening therein. The turntable opening intersects the hopper aperture with each revolution of the turntable on the base. The delivery of balls to the chute is controlled by the speed of rotation of the turntable. The turntable may comprise multiple openings that intersect with the aperture with each rotation of the turntable on the base. In another example, the base of the hopper may further comprise a trigger latch proximate the side of the aperture where the balls may be fed into the aperture. The trigger latch is adapted to detect the presence or absence of a ball in the turntable opening aligning with the aperture during the rotation of the turntable on the base. An electronic processor may be mounted on the support frame and connected to the drive motors and connected to the drive motors and to the hopper turntable motor with the processor adapted to allow a user to control the speed and position of each of the motors. The ball chute defines a passageway for a tennis ball in the path from the hopper to the launch point. A portion of the passageway may be defined by one of the pitching wheels and the diameter of the passageway in this portion is slightly less than the diameter of the tennis ball. The axes of rotation of the pitching wheels are movable with respect to one another where by the trajectory of a ball thrown by the machine may be changed. The guide rails in the ball chute may comprise generally parallel, spaced apart, metal blades. Alternatively, the guide rails may comprise generally parallel, spaced apart, metal wires.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tennis ball throwing machine.

FIG. 2 is perspective view of the tennis ball machine shown in FIG. 1 with the lower, plastic shell housing portion and the top lid removed.

FIG. 3 is a perspective view of the tennis ball machine with the entire plastic shell housing portion removed and the top lid removed.

FIGS. 4A and 4B are perspective views of a tennis ball path from the turntable in the bottom of the hopper at the top through the throwing mechanism underneath. FIG. 4A is shown without any tennis balls, while FIG. 4B shows tennis balls along the path of travel.

FIG. 5 is a perspective view of one example of guide rails in accordance with the present invention.

FIGS. 6A and 6B are side views of a turntable positioned at the bottom of a hopper and adapted to deliver tennis balls into the ball chute. FIG. 6A shows this view without any tennis balls, while FIG. 6B shows sample tennis balls in the hopper and being dropped through the aperture.

DETAILED DESCRIPTION

The tennis ball throwing machine described herein solves, or at least greatly reduces the problems arising from, the issue of debris and dirt build-up in the machine. As will be described, the operating components of the machine are substantially protected from the sun and the environmental elements such as rain and precipitation. However, the bottom of the machine is open to the surface under the throwing machine. Moreover, at least a portion of the ball pathway and chute in the mechanism are open so that debris that may otherwise collect on along ball pathway or otherwise in the machine is free to fall to the surface under the machine.

As shown in FIG. 1, a tennis ball throwing machine 10 includes a plastic shell 12 that covers the exterior of the machine. A top lid 14 is hingedly connected as the top of the tennis ball throwing machine 10 to protect the machine from rain and other precipitation. The machine 10 is easily moved around by a user using the handle 16 and rolling the machine on the large rear wheels 20 together with the smaller-diameter caster wheels 22 on the front of the machine. The machine 10 includes an open front window 18 where the balls that are thrown by the machine will exit the machine. In FIG. 1, the window 18 reveals the pitching wheels 24 together with the launch point 26 which is generally the closest point between the two pitching wheels. In the vicinity of the top and the back of the machine 10, there is shown an interface touchpad 28 that is used to select the tennis ball drills and conduct other communications between the user and the machine.

Turning now to FIG. 2, there is shown a stripped-down ball machine 50 that is similar to the ball machine 10 shown in FIG. 1, except that the ball machine 50 has had the top lid and outer shell removed to show the inside of the machine. The tennis ball machine 50 includes a support frame 51 that is made up of a wheel frame 52, four vertical support members 54, and a support plate 56. The vertical support members 54 are secured on their bottom ends to the wheel frame 52. The vertical support members 54 are secured on their top end to the support plate 56. The plate 56 carries the ball throwing mechanism 70 and the ball hopper 58. The support frame 51 further comprises vertical handle support 60 and a horizontal handle 62.

The wheel frame 52 has large rear wheels 80 connected to the rear portion of that frame and caster wheels 82 connected to the front side of the frame. The large wheels 80 allow a user to more simply maneuver the machine 50. The support plate 56 has the pitching assembly 70 connected to the underside thereof and the ball hopper walls 58 connected to the topside thereof. The hopper walls 58, and especially its outside sidewalls, may form a segment of the outer shell of the machine such as shown in FIG. 1. Alternatively, the hopper walls 58 may form a complete ball container that is removable from and replaceable into the machine 50 and would have an outer shell around it.

The pitching mechanism 70 includes the lower pitching wheel 72 and upper pitching wheel 74. Each pitching wheel 72 and 74 has a ball engaging peripheral surface 73 and 75 respectively on its outside perimeter. The surfaces 73 and 75 may be rubber or some other suitable material. The surfaces 73 and 75 may also be slightly concave in profile to conform to a tennis ball diameter. The spot that is generally the closest spot between the lower and upper pitching wheels 72 and 74 is referred to as the launch point 76. This is generally the location where a ball is thrown from the machine 50.

As is readily evident from FIG. 2 as well as FIG. 3, the machine 50 does not contain any wall or base that encloses the bottom of the machine. Instead, the bottom of the machine is open under and between the wheel frame 52. In this way, any dirt or debris that may enter the machine 50 or the pitching mechanism 70 will fall through the machine and on to the surface underneath the machine.

Turning now to FIG. 3, the machine 50 is the same machine as shown in FIG. 2 except that the hopper walls 58 have been removed. As is more clearly seen, the support plate 56 has a turntable 100 mounted thereon. The turntable 100 is open to the inside of the hopper walls (not shown). The turntable 100 has four openings 102 in it together with funnel portions 104 with each opening that encourages the movement of a tennis ball into the openings. An aperture 110 in the support plate 56 is the outlet where tennis balls from the hopper are fed down and into the pitching assembly 70. The openings 102 align with the aperture 110 to drop the balls into the pitching assembly 70. Although not shown, an electric motor operates the rotation of the turntable 100. In this example, the support plate 56 is the bottom of a hopper. The turntable 100 rotates around inside the hopper to capture and feed the balls to the aperture 110. In alternative embodiments, a hopper may be a single unitary piece having only an aperture in the bottom thereof. A turntable can be rotatably mounted inside the hopper to selectively feed tennis balls through the aperture of a hopper.

FIGS. 4A and 4B demonstrate the path of tennis ball within a machine like machine 10 or 50. Tennis balls are collected inside a hopper (not shown). At the bottom of the hopper is a turntable 100 having openings 102 therein. In this example, there are four openings in the turntable 100. There may be one or more openings depending on the operation and engineering of a given ball throwing machine. The opening 102 has a funnel component (not shown) that helps guide tennis balls into the opening. Below the turntable 100 is the bottom of the hopper which is also the support plate 56. The support plate 56 has an aperture 110 therein that is oriented above the throwing mechanism 70. When an opening 102 in the turntable 100 that has a ball therein is aligned with the aperture 110, the ball will drop through the aperture by way of gravity. The ball is deflected back by the deflector 16. The tennis ball is then in the chute of the ball machine. The chute passageway is defined on one side by the peripheral surface 75 of the upper pitching wheel 74. On the other side of the passageway there is the chute 120. The chute 120 is shown as being made up of four rails or blades 122 and 124. These blades 122 and 124 are aligned so that they are substantially parallel. Spacers 126 separate the rail blades 122 and 124. The blades 122 are on the outside of the chute 120. They contain a tennis ball within the passageway. The blades 124 are set deeper to form a passageway, together with the peripheral surface 75, that is slightly smaller in diameter than a tennis ball. In this way, the spinning of the upper pitching wheel 74 rolls the tennis ball 130 through the passageway along the chute 120 to the launch point 76. At the launch point 76, the tennis ball 130 is engaged by both upper and lower pitching wheels 74 and 72 respectively. The rotation of the upper and lower pitching wheels 72 and 74 throws the tennis ball 130 from the machine.

An additional benefit from the rail ball chute delivery system is the notable tracking consistency of the ball to the pitching wheel launch position. The inner two rails 124 guide the ball to the center of the pitching wheels 72 and 74 each time by steering the ball as it rolls between the upper pitching wheel 74 and the inner two rails. Two rails 124 are used in this example as the rolling surface and the ball is located side to side and guided initially by the outer two ball chute guide rails 122. The increase in consistent launch location tends to add consistent to the pitching spin and trajectory.

The upper and lower pitching wheels 72 and 74 respectively spin around axes 112 and 110 respectively. The axes 110 and 112 are substantially parallel to each other to guide a tennis ball that is pitched from those wheels generally straight in front of the machine. The pitching mechanism 70 is mounted so that the pitching wheels 72 and 74 may be positioned relative to each other to change the trajectory and rotational spin of balls thrown by the machine. For instance, if the lower pitching wheel 72 is generally rotated downwardly, relative to the upper pitching wheel 74, then a ball that is thrown by the pitching machine will have an arc that is more flat to the ground. In addition, by varying the pitching wheel speeds in relation to one another to cause top or backwards spin on the ball, the ball flight characteristics and ground impact deflection characteristics may be changed. In the drawings of FIG. 4, the pitching wheels 72 and 74 are generally oriented so a ball will be thrown upwardly. In the rotation of the throwing mechanism 70, the chute 120 will also rotate with the overall mechanism so that the chute will accurately deliver a tennis ball proximate the launch point 76. Also shown in FIGS. 4A and 4B is a second deflector plate 114 which prevents tennis balls from accidentally shooting upwardly and inside a ball machine where a fast moving ball could possibly damage the parts of the machine inside the outer shell.

FIGS. 4A and 4B are essentially identical except that tennis balls 130 are shown all along the ball path through the machine in FIG. 4B.

FIG. 5 is a drawing of the chute 120 as removed from the ball throwing machine 10 or 50. As is evident from FIG. 5, the chute 120 includes two outside rails 122. These rails are relatively thin sheets of metal that form curved blades. The two interior rails 124 are less wide than the outside rails 122. The inside rails 124 will carry and a support a tennis ball. The outside rails 122 will contain a tennis ball within the chute 120. Spacers 126 keep the respective rails 122 and 124 spaced apart. This spacing allows for open areas 128 between the rails 122 and 124. These open spaces 125 allow for dirt and debris to fall out of the passageway that is defined in part by the chute 120. As explained earlier, there is no bottom wall of the machine 10. Accordingly, the debris may fall through the chute 120 and out underneath the machine onto the ground or tennis court surface.

The rails 122 and 124 may be comprised of aluminum, stainless steel, or other acceptable materials including plastic. Preferably, the metal is not able to rust. If the rails 122 and 124 were to rust, then it could roughen the passageway and affect the delivery of tennis balls to the launch point in the machine.

Also, the rails 122 and 124 are shown in the form of flat sheets or blades of metal. These rails may also be made from wire or bars or other round supports. The round wire pieces may be spaced similar to the blades shown in FIG. 5 so that outside rails are set up higher than inside rails that will primarily carry the tennis ball. It is possible that the wires would be stainless steel wire welded together at a proper spacing or they could have spacers there between. The rails could even be plastic as long as a firm and durable plastic was used. Alternatively, combinations of wire and blade types of rails may be used.

As shown in FIG. 5, the openings 128 comprise approximately more than eighty percent of the width of the chute 120 defined as the distance between the outside blades/rails 122. In alternative embodiments, the space between the outside rails may make up more than sixty percent of the width, or further alternatively, more than thirty percent of the width of the chute. Still further alternatively, a chute may include a surface that is perforated or has slots therein to allow debris to fall through it. This chute is expected to have greater that seventy-five percent open space, or alternatively, greater that fifty percent, or still further alternatively, greater than thirty percent open space to allow debris to fall through.

The chute 120 includes a top end 130 and a bottom end 132. The top end 130 of the chute 120 is near the hopper and the aperture 110 in the bottom of the hopper that allows a ball to feed into the passageway defined by the chute 120. The top end 134 of the inside rails 124 are tapered and pointed to allow for a funnel effect to guide the balls into the passageway.

FIGS. 6A and 6B demonstrate the operation of the trigger latch 106 in conjunction with the turntable 100. As is evident from the drawings, there is a trigger latch 106 that is biased upwardly from the surface of the support plate 56. In operation, as a tennis ball 130 rotates around in an opening 102 as the turntable 100 turns in the clockwise direction, a ball will roll over the latch 106 and press it downwardly. In order to prevent the ball from merely riding up on the trigger latch 106, there is the restraining wire 108 that will force the ball to push down on the trigger latch. The restraining wire 108 also restricts balls in the hopper from entering the open position in the turntable when ne drops into the aperture. When a ball pushes down on the trigger latch 106, the ball throwing machine knows there is a tennis ball in the ready position adjacent the aperture 110. During operation, the balls in a hopper may become jammed, or alternatively the hopper may be almost empty. As a result, the openings 102 do not always have tennis balls 130 in them as the turntable 100 rotates during operation. The trigger latch 106 is electrically connected to the processor that operates the tennis ball machine. When pressed down, the turntable 100 will actuate at the predetermined time to rotate and drop a ball 130 into the aperture 110 so that the ball will be fed into the throwing mechanism. Alternatively, if an opening 102 is empty and does not contain a tennis ball 130, then the trigger latch 106 will remain in its upward position. This signals to the machine processor that there is no ball in the ready position. Accordingly, the processor will rotate the turntable 100 another quarter turn (in this example) to seek a tennis ball that would be in the next opening 102. The turntable 100 will rotate until a tennis ball does arrive and press down the trigger latch 106. In this way, the ball machine can operate consistently and without interruption.

Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification. It is intended that the specification and Figures be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. 

That which is claimed is:
 1. A tennis ball throwing machine for throwing balls of a selected substantially uniform compressible type comprising: a support frame for carrying a pair of pitching wheels and drive motors; the pair of pitching wheels being round and with their axes of rotation being substantially parallel, rotatably mounted on the support frame wherein the wheels each comprise a ball engaging peripheral surface and those respective surfaces are adjacent one another and laterally spaced such that a ball is at least slightly compressed when passing between the surfaces; the pair of drive motors mounted on the support frame and connected one each to the pitching wheels to cause those wheels to rotate in opposite directions at variable speeds; a hopper mounted on the support frame and above the pitching wheels; a ball chute positioned in a path from a bottom of the hopper and a launch point that is proximate the point where the peripheral surfaces of the pitching wheels are closest together, wherein the ball chute comprises a plurality of guide rails that are spaced apart and open between them, and the guide rails are separated at a distance apart to support and direct a ball that maybe carried by the rails, whereby debris is free to fall out of and away from the ball chute.
 2. A tennis ball throwing machine as described in claim 1 wherein the hopper comprises a generally solid base but for a generally ball-sized aperture therein, and the ball chute is connected proximate to the hopper at and around the aperture, and wherein the hopper further comprises a rotating turntable mounted on the base of the hopper, and the turntable has a ball-sized opening therein with the opening intersecting the aperture with each revolution of the turntable on the base, whereby the delivery of balls to the chute is controlled by the speed of rotation of the turntable.
 3. A tennis ball throwing machine as described in claim 2, wherein the turntable comprises multiple openings that intersect with the aperture with each rotation of the turntable on the base.
 4. A tennis ball throwing machine as described in claim 2, wherein the base of the hopper further comprises a trigger latch proximate the side of the aperture where balls may be fed into the aperture, the trigger latch adapted to detect the presence or absence of a ball in the turntable opening aligning with the aperture during the rotation of the turntable on the base.
 5. A tennis ball throwing machine as described in claim 2, further comprising an electronic processor mounted on the support frame and connected to the drive motors and to the hopper turntable motor, the processor adapted to allow a user to control the speed and position of each of the motors.
 6. A tennis ball throwing machine as described in claim 1, wherein the ball chute defines a passageway for a tennis ball in the path from the hopper to the launch point, and further wherein a portion of the passageway is defined by one of the pitching wheels and the diameter of the passageway in this portion is slightly less than the diameter of a tennis ball.
 7. A tennis ball throwing machine as described in claim 1, wherein the axes of rotation of the pitching wheels are moveable respective to one another whereby the trajectory of a ball thrown by the machine may be changed.
 8. A tennis ball throwing machine as described in claim 1, wherein the guide rails comprise generally parallel, spaced apart, metal blades.
 9. A tennis ball throwing machine as described in claim 1, wherein the guide rails comprise generally parallel, spaced apart, metal wires. 